rhbz1124630 - remove client interfaces and most of the RESTEasy dependencies

We have to keep RESTEasy Multipart provider because we need to have those annotations on the Interface and DTO (missing them the server implementation will not work). When we package in fedora, we could make it a buildRequire dependency so RESTEasy won't be pulled in as runtime dependency.
I'm not sure how well Enunciate will handle this - http://stackoverflow.com/questions/5279003/enunciate-not-cant-determine-output-type-for-javax-ws-rs-core-response#comment17024381_5283163 - but perhaps things have changed since then.

If we can't find a solution, we might have to generate Enunciate docs from the implementations in zanata-server, rather than the API interfaces in zanata-api.